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                        懒加载 &amp; didSet
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                            <b>0.12.</b>
                        
                        ATS
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    <!-- Title -->
    <h1>
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        <a href="./" >Swift 简介</a>
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                    <section class="normal" id="section-">
                    
                        <h1 id="%E6%87%92%E5%8A%A0%E8%BD%BD">&#x61D2;&#x52A0;&#x8F7D;</h1>
<blockquote>
<p>&#x5728; iOS &#x5F00;&#x53D1;&#x4E2D;&#xFF0C;&#x61D2;&#x52A0;&#x8F7D;&#x662F;&#x65E0;&#x5904;&#x4E0D;&#x5728;&#x7684;</p>
</blockquote>
<ul>
<li>&#x61D2;&#x52A0;&#x8F7D;&#x7684;&#x683C;&#x5F0F;&#x5982;&#x4E0B;&#xFF1A;</li>
</ul>
<pre><code class="lang-swift">lazy <span class="hljs-keyword">var</span> demoView: <span class="hljs-type">UIView</span> = {
    <span class="hljs-keyword">let</span> v = <span class="hljs-type">UIView</span>(frame: <span class="hljs-type">CGRect</span>(x: <span class="hljs-number">0</span>, y: <span class="hljs-number">0</span>, width: <span class="hljs-number">100</span>, height: <span class="hljs-number">100</span>))
    v.backgroundColor = <span class="hljs-type">UIColor</span>.redColor()

    <span class="hljs-keyword">return</span> v
}()
</code></pre>
<ul>
<li>&#x61D2;&#x52A0;&#x8F7D;&#x672C;&#x8D28;&#x4E0A;&#x662F;&#x4E00;&#x4E2A;&#x95ED;&#x5305;</li>
<li>&#x4EE5;&#x4E0A;&#x4EE3;&#x7801;&#x53EF;&#x4EE5;&#x6539;&#x5199;&#x4E3A;&#x4EE5;&#x4E0B;&#x683C;&#x5F0F;</li>
</ul>
<pre><code class="lang-swift"><span class="hljs-keyword">let</span> demoLazy = { () -&gt; <span class="hljs-type">UIView</span> <span class="hljs-keyword">in</span>
    <span class="hljs-keyword">let</span> v = <span class="hljs-type">UIView</span>(frame: <span class="hljs-type">CGRect</span>(x: <span class="hljs-number">0</span>, y: <span class="hljs-number">0</span>, width: <span class="hljs-number">100</span>, height: <span class="hljs-number">100</span>))
    v.backgroundColor = <span class="hljs-type">UIColor</span>.redColor()

    <span class="hljs-keyword">return</span> v
}

lazy <span class="hljs-keyword">var</span> demoView: <span class="hljs-type">UIView</span> = <span class="hljs-keyword">self</span>.demoLazy()
</code></pre>
<ul>
<li>&#x61D2;&#x52A0;&#x8F7D;&#x7684;&#x7B80;&#x5355;&#x5199;&#x6CD5;</li>
</ul>
<pre><code class="lang-swift">lazy <span class="hljs-keyword">var</span> dataList = [<span class="hljs-type">String</span>]()
</code></pre>
<h2 id="getter-setter">getter &amp; setter</h2>
<ul>
<li>&#x5728; Swift &#x4E2D; <code>getter &amp; setter</code> &#x5F88;&#x5C11;&#x7528;</li>
</ul>
<pre><code class="lang-swift"><span class="hljs-keyword">var</span> _name: <span class="hljs-type">String</span>?

<span class="hljs-keyword">var</span> name: <span class="hljs-type">String</span>? {
    <span class="hljs-keyword">get</span> {
        <span class="hljs-keyword">return</span> _name
    }
    <span class="hljs-keyword">set</span> {
        _name = newValue
    }
}
</code></pre>
<h2 id="didset">didSet</h2>
<ul>
<li>&#x5728; OC &#x4E2D;&#xFF0C;&#x6211;&#x4EEC;&#x901A;&#x5E38;&#x5E0C;&#x671B;&#x5728;&#x7ED9;&#x67D0;&#x4E00;&#x4E2A;&#x53D8;&#x91CF;&#x8D4B;&#x503C;&#x4E4B;&#x540E;&#xFF0C;&#x53BB;&#x505A;&#x4E00;&#x4E9B;&#x989D;&#x5916;&#x7684;&#x64CD;&#x4F5C;</li>
<li>&#x6700;&#x7ECF;&#x5178;&#x7684;&#x5E94;&#x7528;&#x5C31;&#x662F;&#x5728;&#x81EA;&#x5B9A;&#x4E49; Cell &#x7684;&#x65F6;&#x5019;&#xFF0C;&#x901A;&#x8FC7;&#x6A21;&#x578B;&#x7684;&#x8BBE;&#x7F6E;&#x65B9;&#x6CD5;&#x5B8C;&#x6210; Cell &#x7684;&#x586B;&#x5145;</li>
</ul>
<pre><code class="lang-swift"><span class="hljs-keyword">var</span> length: <span class="hljs-type">Int</span>? {
    <span class="hljs-keyword">didSet</span> {
        timeStr = <span class="hljs-type">String</span>(format: <span class="hljs-string">&quot;%02d:%02d:%02d&quot;</span>, arguments: [length! / <span class="hljs-number">3600</span>, (length! % <span class="hljs-number">3600</span>) / <span class="hljs-number">60</span>, length! % <span class="hljs-number">60</span>])
    }
}
<span class="hljs-keyword">var</span> timeStr: <span class="hljs-type">String</span>?
</code></pre>
<h2 id="%E8%AE%A1%E7%AE%97%E5%9E%8B%E5%B1%9E%E6%80%A7">&#x8BA1;&#x7B97;&#x578B;&#x5C5E;&#x6027;</h2>
<pre><code class="lang-swift"><span class="hljs-keyword">var</span> title: <span class="hljs-type">String</span> {
    <span class="hljs-keyword">get</span> {
        <span class="hljs-keyword">return</span> <span class="hljs-string">&quot;Mr &quot;</span> + (name ?? <span class="hljs-string">&quot;&quot;</span>)
    }
}
</code></pre>
<ul>
<li>&#x53EA;&#x5B9E;&#x73B0; getter &#x65B9;&#x6CD5;&#x7684;&#x5C5E;&#x6027;&#x88AB;&#x79F0;&#x4E3A;&#x8BA1;&#x7B97;&#x578B;&#x5C5E;&#x6027;&#xFF0C;&#x7B49;&#x540C;&#x4E8E; OC &#x4E2D;&#x7684; ReadOnly &#x5C5E;&#x6027;</li>
<li>&#x8BA1;&#x7B97;&#x578B;&#x5C5E;&#x6027;&#x672C;&#x8EAB;&#x4E0D;&#x5360;&#x7528;&#x5185;&#x5B58;&#x7A7A;&#x95F4;</li>
<li>&#x4E0D;&#x53EF;&#x4EE5;&#x7ED9;&#x8BA1;&#x7B97;&#x578B;&#x5C5E;&#x6027;&#x8BBE;&#x7F6E;&#x6570;&#x503C;</li>
<li>&#x8BA1;&#x7B97;&#x578B;&#x5C5E;&#x6027;&#x53EF;&#x4EE5;&#x4F7F;&#x7528;&#x4EE5;&#x4E0B;&#x4EE3;&#x7801;&#x7B80;&#x5199;</li>
</ul>
<pre><code class="lang-swift"><span class="hljs-keyword">var</span> title: <span class="hljs-type">String</span> {
    <span class="hljs-keyword">return</span> <span class="hljs-string">&quot;Mr &quot;</span> + (name ?? <span class="hljs-string">&quot;&quot;</span>)
}
</code></pre>

                    
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